The Pokemon anime is a series geared for small children, and so there's some topics that it tends to avoid. For instance, Ash has never really shown romantic interest in any of the girls who follows him around for years at a time, and even his "first kiss" wasn't technically shown on camera.
Death is another topic that the Pokemon anime tends to avoid, especially when it involves Pokemon themselves. We know that Pokemon die: after all, there are Pokemon cemeteries, and Ghost Pokemon, and other grim hints, but the anime has never shown a Pokemon actually die on screen. Sure, there are a couple of movies that have shown Pokemon sacrificing themselves to save the world, but the actual TV show has never really addressed the topic of death...at least not until today.
The latest episode of Pokemon Sun and Moon: The Series changed all that, as a Pokemon's illness and death became a running subplot of the series. During his stay in the Alola region, Ash met and befriended a stray Litten, the Fire-Type cat Pokemon. Although Litten clearly liked Ash, he refused to join Ash's party as it had a more important obligation: caring for a sick and elderly Stoutland. In today's episode, Stoutland's condition worsens, which causes Litten to seek out Ash for aid. Although Ash gets Stoutland to a Pokemon Center for treatment, it's simply too late.
Throughout the episode, we see an old tree shedding leaves outside Stoutland and Litten's makeshift home underneath a bridge. When Stoutland dies, the final leaf falls off the tree and lands on Stoutland's bed. Litten sees the leaf fall and sees Stoutland's bed collapse and realizes the truth: his old friend and mentor is gone.
Litten goes through several days of mourning, laying on the remains of Stoutland's bed as rain falls around him. Ash and his Pokemon comfort Litten, but it's not until the rain stops that Litten finally begins to move on. He finds Ash and agrees to join him after an impromptu battle. So, Ash has a new Pokemon, but only after that Pokemon's best friend/father figure passes away.
For all the complaints that Pokemon Sun and Moon: The Series is too goofy, today's episode reminded fans that the Pokemon anime hasn't lost its touch. It's a surprisingly nuanced episode, one that touches on death and grief in a way that you wouldn't expect from a show that principally features no-consequence sanctioned animal battles!